Why are the Qingming Festivals of the lunar calendar all on April 5 of the solar calendar?

China's 24 solar terms are based on a one-year cycle, and the interval time is basically unchanged, which is mainly derived from the observation of the movement of Taiwan smoke by the ancients. Whereas the time consciousness of the year of the solar calendar is determined according to the sun. So not much has changed.

Qingming Festival is a very traditional Chinese sacrificial festival, on this day, some wanderers have to return to their hometown to sweep the tomb, the country also stipulates the holiday in the Qingming Festival, some friends found that most of the Qingming Festival is April 5th, I want to know if the Qingming Festival is this day every year. So is the Qingming Festival on April 5th every year, and is the Qingming Festival always on April 5th? Here is a detailed answer to this question.

The annual Qingming Festival does not necessarily fall on April 5th, but generally changes between April 4th and April 6th, which means that it is not fixed on April 5th, and may also be on the other two days.

Because the Qingming Festival is calculated according to the Gregorian calendar, not the Gregorian calendar, for example, the Qingming Festival in 2021 is on April 4. Because the earth's rotation is 360 degrees of ecliptic longitude, and when the earth reaches zero degrees of ecliptic longitude, it is set as the vernal equinox, and if it continues to run 15 degrees, it is the next solar term, and there are a total of 24 solar terms throughout the year. The date of the solar terms on the solar calendar is fixed, and due to leap years, there will be a difference of one or two days.

We will find that many years of Qingming Festival will be on April 5, but not all years are like this, to look at the calendar. To put it simply, the date of Qingming Festival is determined according to the season, so the date of Qingming Festival is always not fixed.

This is because the 24 solar terms are subordinate to the lunar calendar but are divided according to the position of the sun, while Qingming Festival is a solar calendar date fixed between April 4 and April 6 of each year in the Gregorian calendar.

The sun departs from the vernal equinox, and every 15 degrees is a solar term; It runs for a week and returns to the vernal equinox, which is a return year, which is 360 degrees, so it is divided into 24 solar terms. The vernal equinox is the ecliptic longitude at zero degrees, when the sun shines vertically on the equator. Therefore, the date of the solar term is relatively fixed in the solar calendar, such as the beginning of spring is always between February 3 and 5 in the solar calendar.

Before the use of the Gregorian calendar (before 1912 in the Gregorian calendar), there was already a Qingming Festival in China, and at that time the lunar calendar was the official calendar used in China, so the Qingming Festival was obviously the lunar calendar, which was calculated according to the lunar calendar.

Because the lunar calendar is a combination of the solar and lunar calendars of a strictly astronomical nature, the solar terms (of the solar calendar) and the lunar calendar are both part of it. Qingming Festival is on the day of Qingming Day in the lunar calendar, that is, the day when the sun sees the yellow longitude as 15 degrees.

Since the lunar solar terms and the Gregorian calendar both belong to the solar calendar, the total of the solar terms calendar days of the Qingming Festival lunar calendar corresponds to one of the three days of April 4, 5 and 6 of the Gregorian calendar, plus the corresponding fluctuations between the lunar solar terms and the lunar calendar dates in the lunar calendar, and there is no obvious correspondence, so it causes the illusion that the solar terms of the lunar calendar belong to the Gregorian calendar, in fact, the solar terms are part of the traditional Chinese lunar calendar, and the day on which it is located is the solar term day of the lunar calendar.

"Qingming Festival" originates from the Qingming Festival in the 24 solar terms of China's lunar calendar. The 108th day after the winter solstice is the Qingming solar term. There are 15 days of Qingming solar terms.

As the Qingming of the solar term, the time is after the vernal equinox. At this time, winter has gone, spring is full of joy, the weather is clear, the four fields are clear, and nature is full of vitality. "Qingming" is a very appropriate word to call this period.

The earth revolves 360 degrees in Qingming Dynasty, and when the earth reaches zero degrees, it is set as the vernal equinox, and there is a solar term every 15 degrees, with a total of 24 solar terms. Therefore, the date of the solar term on the solar calendar is fixed, and there will be a difference of two days due to leap years.

Do you know why only the Qingming Festival in the 24 solar terms is calculated by the Gregorian calendar?

Qingming Festival, according to the solar calendar, it is between April 4 and 6 every year, and it is not fixed on April 5 every year.

As for why the Qingming Festival does not count the lunar calendar, it is a memorable mill, because Qingming is one of the 24 solar terms in China, and the 24 solar terms are divided according to the position of the sun on the ecliptic (that is, the orbit of the earth around the sun). The sun is regarded as departing from the vernal equinox (zero degrees of ecliptic longitude, at which point the sun is perpendicular to the equator), and every 15 degrees is a solar term; It runs for a week and returns to the vernal equinox, which is a return year, which is 360 degrees, so it is divided into 24 solar terms.

The date of the solar term is relatively fixed in the solar calendar, such as the beginning of spring is always between February 3 and 5 in the solar calendar. However, in the lunar calendar, the date of the solar term is not easy to determine, and then take the beginning of spring as an example, it can be as early as December 15 of the previous year, and the latest can be on the 15th day of the first month. Qingming is generally between April and June in the solar calendar, but the definite lunar date cannot be used.

In fact, we can regard the 24 solar terms handed down by our ancestors as the Chinese nation's own solar calendar, because it is calculated and divided by the position of the sun on the ecliptic (that is, the orbit of the earth around the Gaodian sun) used abroad by the solar calendar, and the natural difference is not as big as that between the lunar calendar and the solar calendar.

The Qingming Festival belongs to the 24 solar terms, and the 24 solar terms are compiled according to the changes of the sun, so they coincide with the solar calendar.